PROJECT SUMMARY ? CLINICAL PROJECT Impact of Pregnancy on Buprenorphine Pharmacokinetics and Pharmacodynamics This study proposes to address a pressing need in Obstetric Pharmacology related to buprenorphine treatment of opioid-addicted women. Pregnancy commonly motivates these women to stop use of `?street drugs? such as heroin so they seek assistance by coming to drug centers and being converted to either methadone or buprenorphine. These medications are also addicting but pregnancy outcomes are better with use of these medications than with use of street heroin or other opioid substances. The health care system commonly fails these women as the transition to methadone and buprenorphine is difficult, demeaning and at times does not satisfy their cravings. The failure rate with buprenorphine is 20% with most failures occurring during this transition period. Minimal data exists on dosing of buprenorphine in pregnancy and this may explain the high initial failure rate. This proposal will determine the pharmacokinetics of buprenorphine and determine if there is a better way to gauge dosing based on objective and physiological parameters of satiety. We will also determine which maternal, placental or fetal factors impact the risk of Neonatal Abstinence Syndrome.